Georgetown is the third oldest city in the U.S. state of South Carolina and the county seat of Georgetown County, in the Lowcountry. As of the 2010 census it had a population of 9,163. Located on Winyah Bay at the confluence of the Black, Great Pee Dee, Waccamaw, and Sampit rivers, Georgetown is the second largest seaport in South Carolina, handlin…Georgetown is the third oldest city in the U.S. state of South Carolina and the county seat of Georgetown County, in the Lowcountry. As of the 2010 census it had a population of 9,163. Located on Winyah Bay at the confluence of the Black, Great Pee Dee, Waccamaw, and Sampit rivers, Georgetown is the second largest seaport in South Carolina, handling over 960,000 tons of materials a year, while Charleston is the largest.